Safety device for electric sewing machines



Dec. 15, 1925. 1.565.362

-. M. HEMLEB SAFETY nzvrcz: FOR Emcnuc szwme luwamas Filed April 5. 1923 2 SheetS-Sheet 1 l'hyENTOR WITNESSES BY y I I i I I A'ITORNY Dec. 15, 1925- M. HEMLEB SAFETY DEVICE FOR ELECTRIC SEWING MACHINES Wade; ATTORNEY WITNESSES MA'M Patented Dec. 15, 1925.

- UNITED STATES PATENT OFFICE.

MARTIN HEMLEB, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO THE SINGER MANU- FACTURING COMPANY, ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY.

Application filed April 3,

To all whom it may concern:

Be it known that I, MARTIN HEMLEB, a citizen of the United States, residing at Elizabeth, inthe county of Union and State of New Jersey, have invented certain new and useful Improvements in Safety Devices for Electric Sewing Machines, of which the following is a specification, reference being 7 had therein to the accompanying drawings. This invention relates to electric sewing machines more particularly of the drophead cabinet type. Machines of this type are customarily equipped with an electric motor and a manually operated motorcontroller which is used to start and stop the motor and regulate the speed of the sewing machine.

The main object of the present invention -is to provide a safety device whereby accidental starting of the motor is prevented when the machine is not in use.

The invention comprises the provision of a stop which ,is automatically moved to a position obstructing the movement of the 26 motor-controller mechanism when the sewing head is dropped into the cavity of the cabinet; the stop releasing the motor-' controller for manual operation when the sewing head is raised to operative position. The motor-controller preferably comprises a rheostat connected in the motor circuit and a knee-shift connection for operating said rheostat. For the stop, advantage is preferably taken of the usual lifter-plate which swings downwardly intothe cavity of the cabinet from a horizontal position flush with the top surface of the cabinet to a position below and transverse to such surface. The controller operating connections and lifter-plate are preferably so related that the lifter-plate locks suchconnections against movement when it is depressed to. vertical position and releases such connections for operative movement when it is elevated to horizontal position.

tion is not to be understood, however, as limited to the employment of the movable lifter-plate for this purpose, as advantage may be taken of any part which must The inven- 1 SAFETY DEVICE FOR ELECTRIC SEWING MACHINES.

1923. Serial No. 629,570.

necessarily move when the sewing head is dropped into the cavity of the cabinet, to shift a stop into the path of movement of an element of, the controller operating mechanism.

In the accompanying drawings, Fig. 1 is a front elevation, partly in section, of a drop-head sewing machine cabinet outfit embodying the invention; the cabinet being open and the sewing head in sewing position. Fig. 2 is a front elevation of the cabinet with its parts in closed position. Fig. 3 is a transverse section through the cabinet on an enlarged scale and Figs. 1 and 5 are detail views showing a modifica= tion of the invention.

In the preferred embodiment of the invention, as illustrated in Figs. 1, 2 and 3, 1 represents a drop-head sewing machine cabinet of usual construction having legs 2 supporting the top-board 3 and side and end walls 4 which are disposed immediately below the top-board 3 and define a cavity within which the motor-driven sewing head 5 is housed when not in use. The usual means, including thehinge-pins 6, are provided whereby the sewing head may be raised out of the cavity to sewing position above the latter, in which position the front edge of the sewing machine base or bedplate 5 rests upon the lip 7 of the hinged leaf 8. I

The cabinet 1 is preferably provided with the usual lifter-plate 9 to partially sustain or balance the weight of the sewing head and make it easier for the user to raise the sewing head out of the cavity in the cabinet. The lifter-plate 9 is hinged at 10 to a bracket 11 secured to the cabinet 1, within the cavity of the latter, adjacent the rear end edge of the sewing machine bed-plate 5, so that the lifter-plate may extend alongside said rear end edge. The lifter-plate is formed with a lateral lug 12 which extends under the sewing machine bed-plate 5, as shown in Figs. 1 and 2. One end of a stout coil spring 13 mounted on the bracket 11 extends under the lifter-plate 9 and exerts upward pressure thereon to balance the weight of the sewing head; all substantially as described in the United States patent to Diehl et al., No. 541,474.

The sewing head preferably has mounted thereon the electric motor 14 which, together with the sewing head, is received within the cavity of the cabinetl when the outfit is not in use. The motor 14 is preferably connected by means of a belt .14 :to the sewing machine balancewheel 14'.

The motor is preferably controlled by means of a manually operated motorcontroller which may comprise a rheostat 15 r connected to a knee-shift 16. "The rheo'stat 15 preferably comprises the usual resistorconnected contact points 17 over 'which plays the'swinging contact arm 18 and is mounted in the iron box 19'which is secured tothe rear'wall of'the cabinet within the cavity of the latter. Mounted on the cover 20 of the box 19 is a lever'21 having a pin 22 whiclrpasses through a slot 23 in the cover 20 and is operatively connected to swingthe contact-arm 18. "The spring "2- 1 urges the lever 21' to off position. 7

The lever 21 is connected by means of a link 25 to the arm Qdforme'd at the rear end of arock-shaftQT mounted on'pintles 28, 28, carried, respectively, by the rheostat box cover 20 and a'bracket 29. The rock-shaft 27 is formed at its forward end with an arm 30. the head 31 o'fwhich' is' slotted to receive the: knee-shiftarm- 16. The knee-shift arm 16 is pivotally held in the slotted head 31 by meansoiia screw 32and may be shiftedfrom operating position (full line position, Figs.

lzand to non-operating posit-ion full line position, Fig. 2,. or dotted line position,

Fig.

"The lifter-plate 9 may have fixed to its under side a stop-pin '33 which is so positioned and-related to the arm 210i therheo- 'stat operating connections as to-move into thepath of such arm, as shown in dotted lines in Figs. 1'and'3, when the'sewin'g head is dropped'into the cavity of the cabinet.

When the stop-pin 33 occupies its dotted line al starting of themotor. 'A safety device of this character is particularly desirable in an electric sewing machine cabinet outfit for household use where there isdanger of child- 'ren playing with the knee-shift lever -16 When an elecwhen the cabinet is closed.

tric sewing machine is equipped withthe present improvement it is unnecessary for the user to pay particular attention to the disconnection of thesupply cord' from 'the lamp-socket or base-board receptacle when the 'machine' is not -tobe used, as the mere act of droppingthe sewing head into the cabinet locks the knee-shift against accidental operation.

In the modified form of the invention shown in Figs. 4 and 5, the pin 38 is omitted and an arm 3a is rigidly mounted or formed on the rocksha'ft 27 in such a position that its path of movement intersects the lifterplate when the latter is in depressed position. Thelifter-plate thus serves to block opera tive movement of the knee-shift mechanism when-the cabinet is closed. The expression manually operated is used ,herein vin its usual broad sense meaningoperatedby the user of the machine; it beingimmaterial whether the operation is accomplished by movement of the operators hand, arm, foot or knee.

Having thus set forth the nature of the invention, what I clainrherein is 1. The combination with 'a drop hea-d: sewingmachine cabinet, asewing head adapted to be housed within thecavity ofisuch-cab met or raised to operating positioncabove said cavity, and-an electric motor 5 for. "drivis shifted to housi-ng; position, tor lock said shiftable control element=againstnmovement. '3. lncombination, a. .motor-Idrivenosewang head, a drop-head cabinetahaving a cavity --ada-pte'd for reception 0f: saidsewing head,

a motor-controller fixedly :mounted I :in said cavity, a knee-shift operatively connected at alltimes tovsaidmotor-controller, .-and

--automatic means for locking.saidi:'ln1ee-sl1iit and connections against operative movement a when I the sewing head is lowered in said position it blocks operative movement of the knee-shift mechanism and preventsaccidentcavity.

hlncombinatlon, a drophead-sew1ng machine cabinethaving'a cavity,-a motor- 'ClIlVBIlsewing hea-d hinged to said cabinetto swing mtoand'out of sald eav1ty,a manually-operated motor-controller, and I means movable with the sewing head-into said cavity to a; position blocking movement ofan element of said manually-operated motorcontroller.

5. In combination, a drop-head sewing machine cabinet'havinga cavity, rt-motordriven sewing head-hinged to said cabinet to swing 'into andout of said cavity,a springpressed litter-plateadapted tomove with the sewing head and partially sustain the'weight of the latter, a. manually-operated motorcontroller, and a stop movably associated with said lifter-plate and acting to block 0perative movement of said motor-controller When the sewing head is housed in said cavity.

6. In combination, a drop-head sewing machine cabinet including a lifter-plate, a motor-driven sewing head carried by said cabinet and movable with the liftersplate from sewing to housing position, a. motorcontroller including a knee-shift mechanism, and a stop carried by said lifter-plate in a position to block movement of an element of 1 name to this specification.

MARTIN HEMLEB.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,565,362, granted December 15, 1925, upon the application of Martin Hemleb, of Elizabeth, New Jersey, for an improvement in Safety Devices for Electric Sewing Machines, an error appears in the printed specification requiring correction as follows: Page 2, line 102, claim 2, after the Word interlock insert the Words connected to be operated, and that the said Letters Patent should be read With this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 19th day of January, A. D. 1926.

[sEAL.] WVM. A. KINNAN,

Acting Commissioner of Pa ten-25s. 

